Magnetic pickup having multistyli



May 15, 1951 Y M. WEIL 2,553,492

MAGNETIC PICKUP HAVING MULTISTYLI Filed May 25, 1942 2 Sheets-Sheet 1 INyEN-ron Maw/Izumi@ Wed I y l J5 4 BY Q52? /Qjj/ f -ATTRNEY$ M. WEILMAGNETIC PICKUP HAVING MULTISTYLI May l5, 1951 2 Sheets-Sheet 2 FiledMay 25, 1949 -lNvi-:NTOR Q Maxzm'l'zaw Wezl BY @www ArroRNEYS 4orallyicut record, the

Patented May 15, 1951 UNITED AS TATLES PAT EN T 40 F'FICE MAGNETICPICKUP .HAVING YMUISTISTYLI Maximilian Weil, ScarsdalerN. Y. Application'May `.25, 1949, lseral'No. 95;233 .-19 claims. (c1. ,17e-100.41.)

'l *The `present invention is concerned with sysitems for transratingrecorded sound waves into electrical impulses and is more particularlycon- Jcerned with 4magnetic pick-Laps for phonographs. ns conducive toja clear understanding of ft-n'e "underlying purpose o'f "the invention,it is noted `thatnach of 'various types ci phonograph records requires adistinct 'design 'or stylus `for satisiactory operation. Aiirrasznuchasradio broadcasting stations as fwe'll -as '5t-he 'typical phonograph`owners including-the convention lver'tically out, 'and 'theconventional laterally out discs, the necessity vtor l\cfharlgi-ng to adifferent reproducer 1or `'s't'yll'is ras .different types of recordsare "to 'be played -is an annoyance. The recently @introduced lnuern-'groove V'for long fnlaying record has accentuated the 'need for a"reproducel or 'pick-up capable of vention ftolprovid'e "a graph records"which shall have the versali'ty vto accommodate records or two or "morediire'rent types, such 'fior instance Jas 'the conventional lat-'laterally A"out Yrnicrogroove record and the -I'conve tional verticallyfout record, and 'which `pick-up does 'iot require the constant "changeof reproducer or stylus fas different types of discs are vto be played,but .incorporates each of the various lstyli lin :its construction andTadrnits or playing leach nrecord with "the selected stylus :by Lmerelysetting the lirepnnducer structure vanpropr-rate position for -'thefselected stylus to be 'iin service.

tnofther Iolriect is to prov-*rde fa structureel? the labove type Siriwhich operation of .any 'stylus "is fin rnowise impaired or impeded gasby interaction er kinhase fdistortion 'due to the presence of the otherstyli and the magnetic circuits associtherewith.

Another 'object iis to .provide a `magnetic picknp for the 'above typewhich is relatively (simple :and 'inexpensive in .Constr-'uction, whichhas no 'delicate 'parts that require 'adjustment :and which avoidsduplication of many elements ifor the du- 2516K fm 'I'ilut'ple .ppO'SeS'1 `hch it 'SeIVeS 2.115. SO has relatively low weight vand 'thereforeavoids undue Wear of the record groove.

:According to lone feature of the invention, the lr'nagnetic 'fieldstructure arords a plurality ci 'air gaps Aarranged in *parallel in themagnetic circuit, `each ^air gap being -between a corresponding vv'pair"0i poleconormations. 4Asscmiated with the 'gap "between each 'set of"associated pole lccnormations er the 'magnetieieid `structureis a willhave'a collection o 'various types Tor `records, i

tiny magnetic alloy armature or flux relay :ele-

ment which serves asailux modulator mechanically affixed with respect tothe corresponding stylus. Accordingly the `saine ''x'ed magnetic field'structure lwill serve to energize thevoice coil Trein any selectedstylus without interaction, distortion 'or 'inter-modulation.

According to another feature, the pairs of "po-le conformations 'arearranged at intervals about the forward end `of the magnetic eldstructure, rone on 'an outer or 'encompassing 1element of the magneticlield structure "and the 4`other lon an 'inner 'element rthat "may 'be"and preferably iis "the core which extends 'through the voice coil, thepairs of poles dening gaps vlongitudinally of fand near the Vfree endTof the pick-'111).

YEach stylus with its associated armature :or flux relay element 'orflux vmodulator is desirably rigidly mounted upon a carrying lever orbar of non-magnetic spring `metal removably mounted at its root end to.the structure preferably to the case ofthe unit.

:For use with the `laterally cut sound recordytlre armature or fluxrelay element orfluxmodulator extends and moves laterally with respectto the pole conformations that determine the associated air `gap ofthemagnetic field structure, while Tor vertically cut 'records `thearmature Aor 'flux relay 'element moves inward v`and voutward toward andaway Afrom such air gap.

According to another eature, 'the 'various Styli protrude laterally'from one endfof the unit, 'which unit is rotatably ymounted `at itsother rend vupon the tone arm Aso that it may readily be turned aboutAits axis to place any selected stylus into 0perat'ion.

In the accompanying drawings in which arie :shown one or -more .possible.embodiments of the invention,V

Fig. 1 :is .a perspective view showing 4one embodiment of the magneticpick-up 'asmounted on the tone arm,

Fig. l2 is a Vperspective'view `showing 4the pickup "disassembled fromthe 'tone arm,

`Fig. 3 is a transverse 'sectional view taken .on line 3 3 of Fig. 2,

Fig. 4 'is a perspective 'view with parts removed and broken away oflthe magnetic pick-up,

Fig. 5 is -a View 'in transverse cross section, taken on line 5-5 ofFig. '1,

Fig. 6 is a perspective View of the voice coil element,

Fig. '7 'is a plan 'view on an enlarged scale `of la fragment of the'race of the 'pick-up structure,

Fig. 8 is a perspective view on an enlarged scale of the stylus mountsystem,

Fig. 9 is a forward end elevation of the tone arm and associatedmagnetic pick-up showing the adjustment operation,

Fig. 10 is a view generally similar to Fig. 4, of a modification,

Fig. 11 is a perspective View of another embodiment of the invention,and

Fig. 12 is' a transverse sectional view on line I2-I2 of Fig. 11.

Referring now to the accompanying drawings, the system for translatingrecorded sound waves is shown embodied in a magnetic pick-up unit whichillustratively comprises a magnetic field structure including a sourceof magnetic flux, such as the permanent horseshoe magnet I5, havingmagnetically coupled therewith the pole shoes including an outer elementII and an inner element or core I2 which extends through voice Asillustratively shown, the magnetic eld structure includes an upstandinghorseshoe mag- Y net I5, the poles of which are rigid with pole shoe I6and I 7, the outer extremities of which bars are conformed as a polehead with a multiplicity of pole conformations desirably uniformlyspaced ,along the outer end of the structure.

While the pole head might have any number ,of such poles within thephysieailimits of the construction', there is illustratively shown inFig. 4 and arrangement in which two cf such pole conformationsillustratively both for laterally cut records are provided. To this endas shown, each pole shoe I6, Il is a bar conformed as a channel at thepole end thereof, which channel includes an upstanding wall 2| and aninturned `ledge 22, the extremities of the ledges 22 and thecorresponding side of the underlying bar I6, I'I

having each an out turned tongue 22', 24 and 23, 25, respectively, eachof which constitutes a pole element, the tongues 24 and 25 being spacedfrom tongues 22' and 23 respectively to form a split 'pole element 22',24 at one face and a similar element 23, 25 at the other face.

Desirably the core element I2 is affixed by screw 26 at its innerextremity to a non-magnetic `lug 21 rising from the floor/ of the unitand the outer end of said core carries a head 28 (Fig. 6)

at I9, 20 in Fig. 4 for laterally cut records, and .-f

iixed core element I2 with the respective pole heads or poleconformations thereof may be mounted in any of various possible ways forcorrelation with the vibratory elements to be hereinafter described, thedrawing illustratively shows a housing or case 3| to which the poleshoes I6, I'I of the field structure may be affixed as by upsetting asat 32 an upstanding stud of the case through holes 33 in the pole shoes.To this end corresponding holes 34 in the ledges 34 may serve forintroduction of the upsetting tool. A

' i cover 35 may likewise be affixed by any approprithe poleconformations of the two magnetic ele4 y ments, viz., elements II andI2, are in registry to afford the desired air gap therebetween.

In thev illustrative embodiment shown in Fig. 4 the pole shoe of thecore element I2 is a trans- 'verse bar bifurcated at each end todetermine one split pole I 9, 2!) and a diametrically opposed split pole29 and 30.

As shown in Fig. 4, the split pole I9, 29 of the core element'IZ isadjacent to, butspaced by an air gap from the split pole 22', 24 of themagnet field structure element II and the same relation 'exists betweenthe poles that are diametrically opposed to those just described.

The core element 2 may desirably be made of two generally angle shapedpieces I3 welded together face to face at I3' with their shorter legsdiverging or radiating outward to form the poles. While thelxed magneticstructure described,

"composed of the magnet eld element I l and the ate means such as rivets(not shown), to the -upper rim of the case 3|.

As Vshown in Fig. 7, in the space between the portions I9 and 2) of eachpole conformation of `thercore element I2 and the space between theassociated portions 22 and 24 of the corresponding pole conformation ofthe field element II is a tiny magnetic alloy armature or flux relayelement or modulator in the form of a thin, soft magnetizable plate atand which bridges across the air gap intervening between suchconformations. In the embodiment for laterally cut records, one end ofthe armature or flux relay strip 36 is lodged in the space between poleconformations 22', 24 of the field structure II and near the other endthereof in the space between the associated pole conformations I9, 20 ofthe core element I2. Rigid with the armature or vflux relay strip 33 isthe stylus 31 which pro- -protrudes downward from the case and stylus 38upward from the cover 35.

While any suitable system might be employed for mounting the stylus andits associated arma,- ture or flux relay element to respond to themove'- ment impressed thereon by the sound record, it is preferred toaffix these elements to a spring metal stylus lever or bar 39 removablymounted on the body of the unit. In a preferred embodiment shown, thatbar is a cantilever of highly tempered non-magnetic spring material suchas beryllium copper. Preferably the lever 39, the main length of whichextends in a horizontal plane parallel with the armature or ux relaystrip 36, is twisted at right angles as at 40 adjacent the cylindricalmount 4I thereof formed integral with the root end of the bar.

Each stylus system is accommodated in a groove 42 longitudinally of thecase as shown, each stylus system having its own independent mount, andthe cylindrical mount is disposed in a corresponding cylindrical bore 43in the case and has a unitary-tongue 44 near the lower edge of saidcylinder, said arm having an inturned toe 45 that precludes rotarymovement of the mount in either direction.

It will be understood that oneof the 'stylus lever assemblies, such asshown in Fig. 8, is associated with the air gap between correspondingpole conformations I9, 20, 22', l24 and 29, 3D, 23, 25 of the magneticelements I I and I2 of the magnetic circuit. v

Desirably the magnetic pick-up unit has a plug and socket mount at itsinner or root end with respect to the tone arm and said mount is soconstructed as to admit of positioning the u nit selectively for placingany one of the plurality f of styli in operative engagement with therecord to be played. In the embodiments specifically shown, the root endof the pick-up unit has Va plug 45 fitting into a corresponding socket41 of the tone arm and adjustable by turning in said atrasos socket ierselection of the stylus to be used. As applied to the .two-stylusembodiment illustratively shown, the plug has a semi-circular .groove 48which rides the tip end 49 tof a .screw 50 in the tone arm, the two ends:of the semi-circular track `determining respectively the .setting shownin Fig. l3 in which stylus ..31 is .lowermost and Fig. `2 which stylus38 islowermost. ,Preferably .-a set screw 5I locks .the Yplug -46 in anyset position.

The tone arm is desirabl-y made with a `forwardly protruding ledge 52extending over the length of the pick-up unit for protection thereof butspaced therefrom .-suilciently to permit the ,rotary movement vthereoffor .setting desirably 'by pushing against grip fingers V53 ,protrudingfrom the forward end of .the case-I.

A.In operation, with a vlaterallyfcut record as .lateral vibration ,is,impressed upon the stylus, its associated armature ,or flux relayelement 36 moves therewith .as best shown in Fig. '7, in the 4air gapbetween the pole conformation Y2.2, 24 of the magnetic eld structureelement Il and the pole con-formation I9, 2.0 of the core element 1.2.As the armature or flux relay strip 36 lapproaches pole portion 22, amagnetic flux passes therefrom through the llength of .said .armature orflux relay element 36 thence through pole portion I9 and the magneticcor-e l 3 to the opposite pole -of magnet I5. When the armature or uxrelay strip .36 now swings under vibration of thestylus in the oppositedirection 'to approach pole portion 24, the circuit is .in reversedirection from .magnet L5., through core i3, core pole l and through thelength of the armature .or ux relay strip 36, thence by way of poleportion .24 through pole Shoe l'l to the opposite pole of magnet l5..The reversal of magnetic .nx through the core induces an E. M. F. Vintothe voice coil in manner readily understood.

.As will be readily seen, the pole conformations associated with thevarious armature or magnetic flux relay element of the. unit larearranged vin parallel and not in .series so that regardless 'how manyStyli and associated armature'or flux relay elements are employed on theunit, there will and can be no interaction or .distortion as., forinstance, by inter-modulation even though foreach stylus one and thesame fixed magnetic circuit is used. In fact it is only the small poleelements of said vcircuit and the armature or magnetic 'flux relayelements that are individual to each of the several `styli and these, asabove noted, are arranged in parallel.

The arrangement set vforth thus promotes simplicity and lightness ofconstruction .and affords facsimile reproduction.

l While the vindividual stylus systems could be identical to admit ofconvenience in shifting Styli for playing records of one and thesametype, the invention yhas its most important eld of application, as abovesuggested, to a more or less universal magnetic pick-up adaptable to anyand all of various types of `sound records including laterally andvertically cut sound records and micro-groove or long playing records,whether of either .or both the laterally cuter vertically out type, aswell as .other types of records, if `any there be. The ystylus leverassembly need merely be tdesigned for the particular type of lrecord forwhich it is intended and the unit may be made with as many .of thedistinct types of `stylus and mou-nts therefor .as is desired. f

The embodiment .ofFigs 1 to i for instance,

which shows .a two-stylus system, both `for .latorally `.cut records.,mig-ht utilize one stylus 31 for ordinary laterally cut records and .lamore slender stylus 38 might be carried by the other :stylus lever, tobe suitable Yfor the long Apla-ying vor :micro- `groove laterally :outrecord.

`In the alternative vembodiment 'shown in Fig. l0., the pole system nearthe bottom of the fig-ure is identical with that of Fig. 4, but thatshown at the top of the figure is designed fora vertically cut record:in that the pole Iconformation V Yat the top of the magnet bar Il' hasa single rather than asplit pole, as has also the corresponding end i8of the vcross bar on the fixed core element i3. The armature or magneticflux vrelay strip (not shown) would of lcourse bridge across 'and abovethe air gap between poles 5.5 and I8 andthe stylus lever 39 would flexup and down in operation.

.In Figs. 11 and 12 is shown an embodiment of the invention toaccommodate three styli'. The magnetic eld structure comprises asourceof magnetic flux ll, an inner pole shoe 'or core element iii) andan outer pole shoe element 6I, all magnetically coupled together. Thevoice coil 62 surrounds the core element @El and is in turn within theouter element 6I. The core 'element 6@ has a pole head 68, preferablyintegral therewith, shown with three outwardly radiating poles 541,185and o6. The outer element 5| ha'sa similar pole head el also preferablyintegral therewith, whose three poles, two of which rare shown at G4 and6'5" match those of the Icore .and are in registry therewith, but spacedtherefrom, preferably bythe thickness of the ange 63 of the voice coilspool which is interposed between said heads.

Desirably the 4core element 68 `is tubular and the outer Yelerrient 5'!is likewise tubular, that is, in the form of a cylindrical shell asshown. To avoid -eddy currents, the core tube vtil is preferablylongitudinally split as at 69 and the shell is likewise longitudinallysplit as at 10.

While the magnetic vconnection between the core 68 and the outer element6| of the field structure .may be of any of Various constructions, apermanent magnet plate. or disc 'H which .is magnetized radially withone pole at the center and 'the opposed pole 4at the periphery is desirably disposed against and superposed over the rear ends of said poleshoe elements 68, 'EL By virtue of its permanet magnetism, the disc 'Hremains in secure engagement with the two elements Si) and 8l whichinturn remain assembled by Virtue of their fairly tight fit with respectto the voice coil 6-2.

The magnetic field structure is preferably of high quality magneticalloy, and the outer tube or ishell 6l thereof affords excellentshielding' manner .similar to the mount shown in Fig. 7..

For the laterally -cut record, the stylus lever differs somewhat inVconstruction fromA that shown in Fig. 8 in that the twist l5 is notnear the mount end as in Fig. y8 but near the free end 16. That twist infact is beyond or to the left of the pol-e head 53 of the core fill. .Asecond difference is that the armature'or magnetic ilux relay plate Tl,unlike that shown in Fig. 8, is mounted `beyond or to the right of thetwisted portion l5 and at a distance from thefstylus lil. That plate 11extends for the upstandingwidth of the 'Stylus lever 13 and is of lengthto extend across the thicknesses of each of the pole heads 64 and 61 andto straddle the air gap therebetween, as shown. u

f It will immediately be apparent that in use of the magnetic pick-upshown, the stylus 18 when :following a laterally cut record, will movethe armature or ux relay plate 'l1 toward and away from the poles 64 and64 and thereby modulate the magnetic flux through the eld, withinduction of an E'. M. F. in the voice coil 62 in manner readilyunderstood.

The poles 65 and 55 are shown similar' in shape to poles 64 and 64 andsuitable also for laterally cut records and may have a stylus (notshown) for the micro-groove type of record, where stylus 'i8 is say forthe conventional type of laterally cut record.

Pole 6B and its companion (not shown) are of somewhat different shape,each with a squared end 66B. Such shape of poles serves for thevertically cut record, in which the armature or flux relay plate (notshown) would extend in the same plane as the outer end 'H9 of thecorresponding stylusl lever. To that end, the twist of the stylus lever79 would of course not be near the outer end as at 15 but beyond or tothe right of the pole head 51. In other words it would be substantiallyin the location shown at Mi in Fig. 8. Asis obvious, the armature or uxrelay plate for the vertically'cut record would move radially inward andoutward with the vertical movement of the stylus toward and away fromthe square ended pole 665a and its companion (not shown), the air gapbetween which poles is straddled by the armature or flux relay plate.`While the embodiment of Figs. l1 and l2 is shown with three poles, itis of course obvious that it could be incorporated in a magnetic pickupwith but two poles or with four or more poles and corresponding numberof stylus levers and styli.

.The mount of the embodiment of Figs. 11 and 12 might be similar to thatof the other embodiments, modified of course to accommodate the greaternumber of settings.

As many changes could be made in theV above construction and manyapparently widely different embodiments of this invention could be madewithout departing from the scope of the claims, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent of the United States is:

l. Atduplex magnetic pick-up for alternative use for each of two typesof sound records that require different styli, said pick-up comprising amagnetic eld structure, including an outer element and a core element, avoice coil about the latter and within the former; said outer elementand said core element each having two pairs of opposed poles, therespective pairs of the outer and of the core elements being near butspaced from each other to form a gap, a pair of Styli, each stylushaving a lever mounted in fixed relation with respect to the magneticeld structure, each stylus having a separate and distinct armature rigidtherewith, each of said armatures being mounted in the magnetic field ofthe corresponding air gap between the pole pairs of both the outer andthe core structure elements, and means displaceably mounting saidpick-up to permit positioning the same alternatively, face up or facedown, depending upon the stylus selected for use.

2. A duplex magnetic pick-up for playing alternatively conventional andmicro-groove records, said pick-up including a magnetic eld structurecomprising an outer portion and a core portion, a voice coil about thelatter, said outer portion having two pairs of poles arranged inparallel said core portion having a double-yoke pole head at one endthereof with the arms of said pole head extending, respectively, nearbut spaced from the respective pairs of polesI of said outer portion, apair of separateand distinct stylus carrying levers pivotally mountedwith respect to the magnetic eld structure, each having a stylus nearthe free end thereof, said styli being differentiated, one forplayingconventional records and the other for playing micro-groove records',each stylus having a separate and distinct armature rigid therewith,each of said armatures being magnetically insulated with respect to thecorresponding stylus mount and bridging the gap between the poles andthe corresponding yoke pole head of the magnetic core.

3L A magnetic pick-up to serve alternatively for playing laterally cutor vertically cut phonograph records, said pick-up comprising a magneticfield structure consisting of a source of magnetic uX, an outer shoeportion and a core pole shoe portion, said core portion having a polehead transversely across the free end thereof and bifurcated at one endthereof, said outer portion having a pair of spaced pole portions nearbut spaced from said bifurcated pole and presenting an air gap withrespect to said bifurcated pole end, said structure also presentingasingle pole shoe having an air gap with respect to the other end of thepole head of said core portion, a stylus having a mounting lever pivotedwith respect to the field structure and havingr an associated armaturesubstantially in the space between the pole portion of the outer portionand bridging between said pole portions and the associated bifurcatedend of the pole head of the core portion, and a second stylus having amount for accommodating the movements impressed by a vertically cutrecord, said latter stylus having an armature across the gap between thesingle pole of the outer portion and the associated end of the pole headof the core portion, said magnetic pick-up having mounting facilities topermit use thereof with either of the two opposed styli resting upon therecord to be played.

4, A magnetic pick-up comprising a case having a mounting end and a freeend. said case having a magnetic eld structure comprising an outerportion and a core portion with poles on the respective eld structureportions spaced from each other to present air gaps therebetween inparallel near the free end of said case, said pick-up having styli eachhaving rigid therewith, a separate and distinct armature, each of saidarmatures being in the magnetic eld of the corresponding air gap, eachstylus protruding outward from the pick-up, a xed mounting structure forthe pick-up, said mounting structure being a socket and said pick-uphaving a complementary plug displaceable with respect to said socket, topermit mounting the pick-up in position for one of the styli at will tobe directed for riding upon a sound record.

5. The combination recited in claim 4, in which the mounting structurefor the magnetic pick-up is a tone arm, and means are provided to limitmessage' 9 thedisplacement of the pick-up insaid' socket for' theselected stylus to poi-'nt downward, and in which the tone arm has avprotrudingv ledge extendingv over the length of themagnetic pick-up andspaced therefrom suiilciently' to permit of said rotary adjustmentthereof;

6. A1 magnetic pick-up comprising a hollow case, a magnetic fieldstructure therein compris-A ing a horseshoemagnet, pole" shoesprotruding from said'magnety andv having a plurality of pairs of polesarrangedin parallelatthe free end thereof, another pole Vshoe'comprisinga xed magnetic core with a voice edili thereabout,said core having apole head at thei reeerid thereof spaced from., the previously; recited'respective pole pairs to present air gaps therebetween, a plurality' oilstyli each having .its individual mount upon the case for freedom' ofdisplacement jofjthe stylus under' the action ofthe record upon which:it rides, each stylus'having'a separate and distinct4 armature rigidtherewith, each. of said armatmesbridging the corresponding gap. betweenthe said" associated polev shoe pairs and means iorfadjustably mountingthe magnetic pick-up in position selectively to dispose -any one of thestyli in playing position;

' 7. A magnetic'pick-up comprising a generally rectangular case, anouter magneticgeld structure therein' comprisingan upstanding `horseshoemagnet, a pair of ypole shoes extending forward therefrom in said case,each pole shoe having a pair of opposed poles, 'the poles of theopposite pole shoes being spaced from each other to define air gapstherebetween respectively near the opposite faces of the case, a mountin the case near the upstanding horseshoe magnet, an inner magnetic coreconstituting part of the magnetic field structure, aflixed upon saidmount at one end thereof, a voice coil thereabout, said core having apole head at the opposite end thereof with poles at the extremitythereof near the respective pole pairs of the outer magnetic iieldstructure, a pair of Styli each having an armature rigid therewith andin the magnetic elds of the respective air gaps between the poles "ofthe respective outer magnetic `eld structure and the adjacent pole headof the magnetic core, each stylus having a mounting lever affixed to thecorresponding face ofthe case and said leverfbeing of highly temperedspring metal readily to ilex under the vibration imposed upon thestylus, and means for mounting the magnetic pick-up with either face ofits case uppermost, selectively to place either stylus in operation.

8. A magnetic pick-up comprising a magnetic field structure including acore element and an outer element connected in magnetic circuittherewith, a voice coil about said core and within said outer element,pole heads extending outward from the outerend of the core and poleheads extending outward from the outer end of the outer element, saidpole heads being spaced from each other and including poles, each poleof one pole head being substantially in registry with the correspondingpole of the other, stylus levers rigidly mounted with respect to the eldstructure, each stylus lever having a separate and distinct armature,each armature extending across the proximate edges oi the correspondingpoles of the pole heads and in the magnetic eld of the air gaptherebetween, the stylus of each stylus lever'being mounted near thefree end thereof beyond the pole heads.

9. The combination recited in claim 8, in which the core and the outerelement of the eld struc- 101 ture are both Atubular and are bothlongitudinally slotted to mimmize eddy currents.

19; -The combination recited -in claim 8f, in which the magneticconnection between the core and the outer' element of thek magnetic eldisa permanent magnet plate against the rear ends oi said twofieldelements.

lhThe combination recited in claim 8'-, in which each stylus lever hasan anchor mount on a non-magnetic lug aiiixed to the'V outer fieldelement in which the width of the stylus lever adjacent saidmountextends radially of said eld elementl and the outer part' of' the styluslever beyond the pole h-eads extends-'at rig-ht angles to the mount end.f f Y 1 512. The'lcombination recited claim 8, in which eachstylusflever for-fa laterally cut record has its widthextendingrradiadly ofthe outer elcl element at `the region spanning thepoles and in whichl the edgesfor said poles adjacent said spanningportion extend substantially parallel to the corresponding magnetic iiuxrelay element.

131.' The combination recited* lnclaim 8, in which any` stylus lever'for accommodating ver tically eut recordshas the portion oi the lengththereof which spans thecorresponding polesy Yextending in its width atrigh-t angles tothe corresponding radiusfof' theL outer eld element andthe associated poles extend parallel thereto at their free edges; i v

U 1141. VAi magnetic pick-up comprising amagnetic eld structureconsisting of a source of magnetic flux, and inner and outer pole shoesmagnetically coupled to said source, said pole shoes having polesarranged in pairs, the poles of each pair being on the respective innerand outer poles shoes and spaced from each other defining an air gaptherebetween, a voice coil about one of said pole shoes, a plurality ofstyli, each stylus having its individual mount each of said mountshaving aixing means at one end thereof and carrying a vstylus at itsfree end, said mounts being free to vibrate at the stylus-carrying endthere-,-

of, each stylus having a separate and distinct armature rigid therewith,each of said armatures being disposed in the magnetic eld of thecorresponding air gap dened by each of said pairs of poles.

15. The combination recited in claim 14, in which the pick-up has alongitudinal axis and means for mounting said pick-up for displacementthereof at will about said axis to any of a plurality of settings forselectively placing into operation any one of the styli.

16. A magnetic pick-up comprising a case, a magnetic eld structuretherein, consisting of a source of magnetic flux and inner and outerpole shoes magnetically coupled to said source, a voice coilencompassing one of said pole shoes, each of said pole shoes having aplurality of poles near one and the same end of the pick-up, the polesof the inner as Well as those of the outer pole shoes being beyond theend of the voice coil and said poles being arranged in pairs, the

poles of each pair being spaced from each other to define an air gaptherebetween, stylus levers each having its own independent mount uponthe case, and associated with the respective air gaps, each of saidstylus levers having a stylus near its free end and having a separateand distinct armature rigid with said stylus, each of said armaturesbeing disposed in the magnetic eld of the corresponding air gap.

17. A magnetic pick-up comprising a case, a magnetic eld structuretherein, consisting of tive poles on the core portion and spacedtherefrom to present air gaps therebetween, said air gaps being arrangedin parallel, stylus levers mounted on the case and associated With therespective pole pairs, each lever having a stylus near the free endthereof, and each lever having a separate and distinct armature rigidtherewith each of said armatures extending in the magnetic eld of thecorresponding air gap.

18. The combination recited in claim 17, in which the pick-up has amount at the end thereof opposed to that of said styli and rotatablevabout the longitudinal axis of the pick-up for turning the entirepick-up in order to permit of setting thereof for placing into operationthat stylus selected for servicei 19. A multiple magnetic pick-up forplaying any of a plurality of types of phonograph records, said pick-upincluding a magnetic eld structure consisting of an outer portion and acore portion, a voice coil about the latter, each of said magnetic eldportions having a plurality of corresponding poles, each pole of eachportion being opposed to a corresponding pole of the other portion andspaced therefrom to present an in- 12 tervening air gap, aplurality ofdiverse styli each mounted in fixed relation to said structure, suchstylus being of type adapted for the respective types of records, themount of each stylus being of type to afford the freedom of movementappropriate to such stylus, each stylus having a separate and distinctarmature rigid therewith, each armature being disposed in the magneticfield of the corresponding air gap.

WEIL.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNrrED STATES PATENTS Number Name Date 1,570,297 Dyer Jan. 19, 19261,704,511 Nakken Mar. 5, 1929 1,778,401 Pratt Oct. 14, 1930 1,958,386Thomas May 8, 1934 1,992,893 Thomas Feb. 26, 1935 2,197,967 Dally Apr.23, 1940 2,318,308 Harris May 4, 1943 2,388,116 Bruderlin Oct. 30, 19452,452,304 Hutter Oct. 26, 1948 OTHER REFERENCES The Recording VandReproduction of Sound, Radio News, Nov. 1947, page 50.

